The present invention relates to the analysis of a long data record in a memory, and more particularly to a data analysis where the long data record contains repetitive data over a period of time.
Digital oscilloscopes acquire data in response to a trigger event. The amount of data acquired for each trigger event may be specified by a user. For sporadic events or other pulse events the data of interest is centered on a pulse characteristic, such as pulse width, rise time, fall time, etc. Digital oscilloscopes have acquisition memories capable of storing millions of data points. To make optimum use of the acquisition memory, it is generally desirable to acquire only the data associated with the particular trigger event. Therefore each data acquisition may only acquire a limited number of points of data. Each data acquisition may be considered to be a segment or frame, with each frame generally being of equal length. However this still means that there are potentially tens of thousands of frames stored as a long data record in the acquisition memory. The problem exists in analyzing all of these frames in a timely and useful manner. The analysis may be related to a pulse shape or a pulse interval. For example on a display one frame is displayed at a time, as shown in FIG. 1. The user may scroll through the acquisition memory one frame at a time and visually compare the current record with a reference waveform, shown in a contrasting shade or hue together with the presently displayed frame. A delta time may also be calculated between the reference or first frame in the acquisition memory and each subsequent frame as a timestamp for interval timing analysis. Further the user may set up a summary frame that is the average of all frames or an envelope view of all frames as the reference frame. The user may also display a timestamp table, also shown in FIG. 1, that requires scanning multi-digit numbers, such as 18 digits, to locate records that deviate significantly from one another, indicating problem areas. As with scrolling through the frames, the scanning of large columns of numbers is very time consuming. Scrolling and scanning are only used to locate potential problem areas. Additional effort is required from the user for any statistical analysis, for example by exporting the timestamp data to an external program, such as the Microsoft® Excel program, to create a graphic display.
The problem is multiplied when the memory is not segmented and the entire long data record is being analyzed. The user has to scroll through the long data record looking for problem signatures, either in the waveform shape or in the repetitive nature of the data.
What is desired is a data analysis technique that provides easy analysis of long data records within the acquisition memory of a digital oscilloscope to assist the user in determining trends and problem areas in an expeditious manner.